Typical Faults to Expect in Heating Systems

After the heating being switched off for the summer months, as the temperature starts to plummet and the darker nights draw in, it’s natural to think you’ll be able to simply turn your heating back on.

Unfortunately it’s typically at this time that you’ll notice a problem in your heating system.

After being dormant for so many months, it’s not uncommon for faults to appear as you rev up the system ready for action.

Here’s a brief overview of the some of the simplest and most common faults which you might find in your heating system.

Hot water and cold radiators (or hot radiators and cold water)

This fault relates to radiators which are totally stone cold, not warm in parts and cool in others.

The first thing to check before proceeding any further
is the thermostat; this could be located on the wall around the house or possibly on the boiler itself. Make sure it’s not set to the minimum; crank it up to between 17-20 (for those with numbers) and see if you can hear your radiators and hot water starting to gurgle and get to work.

If that fails, try taking a look at the programme timer next to see if that is preventing the heating from kicking in.

Those are the easy fixes; if you are confident in delving a bit deeper, you could try checking the motorised diverter valve to see if the switch is flicked the wrong way or possibly the pump. If it’s the latter, you’ll be looking for an obvious blockage or lots of muck; if you see either of these a good clean might sort out the problem.

Another potential issue with the pump is trapped air. Bleed the air from the pump
by turning the nut valve and then tightening again. You’ll know it’s time to do it back up when dirty water starts to leak out!

If you’re not sure about how to deal with these more advanced plumbing steps, or they fail to identify the problem, call a plumber to fix the fault.

Radiator is cold at the top

This heating fault can prevent a radiator from efficiently heating a room but the good news is that it’s one of the easiest to fix, often without calling a plumbing too.

It’s caused by trapped air in the radiator which is what prevents the hot water from circulating. To rectify, you simply need to get rid of the air by bleeding the radiator.

To bleed the radiator, turn off the power and place a bucket under the valve. Using a radiator key turn the valve 45-90 degrees and listen to the air hiss out. When dirty water starts to trickle through, the trapped air should be gone and you can tighten it back up again.

This should fix the problem.

Radiator is cold at the bottom

This is not caused by a problem with trapped air, but potentially sludge in your system. If multiple radiators around the house are affected and it’s never been a problem before, you might have a faulty circulating pump.

If you are reasonably proficient you can probably fix sludge in your system yourself. You will however need to remove the radiator from the wall flush it out completely and then replace it.

If you don’t have at least a rudimentary understanding about plumbing, this job is probably not for you and you should call a plumber in. If multiple radiators are affected or the circulating pump is faulty, you will need a plumber anyway.

Other Problems

There’s a myriad of minor issues which could cause your boiler to either stop working, start leaking or to begin making strange noises, such as whistling and thumping.

Amongst the possible causes are water leaks, poor water pressure, valve problems or even just limescale.

Trying to fix it yourself could take a very long time and you might cause more damage if you don’t know your way around a plumbing system. A plumber will recognise the tell-tale signs of each fault and will be able to get your heating back on in next to no time.